Operating mechanism



Jan. 15, 1935. vc. THUMIM OPERATING MECHANISM Filed May 18, 1932 Ihvehtoh CaY'l ThumiTn WM His Attov'hqg.

Patented Jan. 15, 1935 UNITED STATES PATENT OFFICE eral Electric Company,

York

a corporation of New Application May 18, 1932, Serial No. 612,055 Claims. (Cl. 200-89) My invention relates to operating mechanisms, more particularly to operating mechanism of the trip-free type wherein the means to be actuated may be instantly released, either during or after 5 the period of actuation, independently of the actuating or motive means; and more particularly to operating mechanism of the trip-free type for effecting the closure of electric circuit breakers.

The operation of apparatus, as electric switches or circuit breakers for example, by trip-free mechanism is old and well known practice. However, this type of mechanism has long been subject to a number of disadvantages which include complicated and involved linkage structure and the difilculty of obtaining a sensitive and stable trip without further complicating the structure.

A principal object of my invention is the provision of an improved operating mechanism of the aforesaid type which shall be simple and economical in construction to the extent that a minimum of moving parts are involved, eflicient and reliable in operation, and which may be tripped by a very small tripping force as compared with the reacting force to be overcomeor released.

A further object of my invention is the provision of improved tripping means for operating mechanism of the character above referred to which shall be stable under the actuating impact, thereby precluding premature tripping.

My invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawing, Fig. 1 is an elevational view, partly in section, of operating mechanism embodying the present invention; Fig. 2 is a partial view oi the mechanism shown in Fig. 1 at the instant of tripping; Fig. 3 is a diagrammatic illustration of the forces involved in the above mechanism, and Figs. 4 and 5 illustrate other forms the tripping mechanism may assume.

The operating mechanism shown in Figs. 1 and 2 comprises motive means 1, as a solenoid actuating means, and a rod member 2 which is operatively connected to the means to be actuated, which, by way 0! example, may be an electric switch or circuit breaker although it shall be understood that my operating mechanism is u not limited to such specific application.

The mechanism interconnecting the actuating means 1 and the rod 2 includes collapsible thrust-transmitting structure which is trip-free in operation, that is, the rod 2 may be released at any time during or after the closing stroke of the solenoid, and comprises a member or link 3 pivoted at one end, as at 4, and coacting at its other end with tripping means 5. The link 3, restrained by the tripping means 5, forms a fixed mounting for a floating member 6 pivotally carried, as at 7, on the link 3 and operatively connected, as at 8, to the rod 2 at one portion thereof. The floating member 6 is arranged to be rotated about the restraining pivot 7 by the actuating solenoid 1 so as to cause positive movement of the rod 2, the rod 2 when actuated by the operating mechanism moving downwardly to the position shown in Fig. 1 which represents the rod 2 in the fully actuated and restrained position.

Referring more specifically to the solenoid actuating means, a suitable housing 9, in which the aforesaid mechanism is disposed, likewise supports the solenoid which includes an energizing coil 10, a plunger 11 having secured thereto a stem or extension 12 extending through and guided in the armature 13 forming the upper part of the solenoid. The plunger is supported at the lower part of the solenoid in the deenergized position by a cup-shaped member 14 which completes the magnetic circuit of the solenoid and secures the solenoid to the housing 9 as by the bolts 15.

The stem 12 of the solenoid plunger is in alinement with a roller 16 carried at the free end of the floating lever 6 so that when the solenoid is energized the upward stroke of stem 12 causes rotation of the floating lever 6 to the position shown. The floating lever is held in this position by a prop 17 pivotally mounted at 18 and normally biased, as by a spring 19, in a clockwise direction so that the supporting edge 20 of the prop rides under and supports the roller pin 21. The supporting edge 20 is concentric with the pivot 18 so that the pin 21 does not con- 46 4 tribute to the bias of prop 17. Further movement of the prop in clockwise direction is limited by the stop portion 22 which engages the armature 13. Accordingly, after the actuating stroke the solenoid may be immediately deener- 50 gized so that the plunger 11 drops to the lower position shown.

The tripping means 5 may assume a number of forms, a preferred arrangement shown in Figs. 1 and 2 comprising a pivoted latch member 23 biased in a counter-clockwise direction against a stop pin 24 as by a spring 25. The latch 23 is engaged at its camming edge 26 by a roller 27 carried at the free end of the link 3 so as to restrain rotation of the link 3 in a counterclockwise direction. Actuation of the latch 23 is efiected by a tripping solenoid 28, the plunger 29 of which is arranged to engage the latch extension 30 so as to cause counter-clockwise rotation of the latch and release of the roller 27.

In the operation of mechanism having a sensitive trip, the buifer impact caused by energization of the actuating motive means, as a solenoid, may be such that the mechanism is prematurely tripped due to the shock transmitted to the sensitive latch. This is particularly true when the plunger of the trip coil is guided for vertical movement so as to actuate the latch upon upward movement of the plunger. The closing shock may, under certain conditions, be such that the trip coil plunger is vibrated or bounced upwardly so as to cause premature tripping of the latch. Resilient means, such as springs, for preventing such premature tripping would, of course, greatly lessen the sensitivity of the trip.

The above disadvantage is overcome in the present instance by locating the longitudinal axis of the trip coil plunger in a horizontal plane or in a plane slightly inclined with respect to the horizontal. The latch is likewise of small mass and of such dimensions that it is not likely to whip open ,when subjected to'( shock. As, shown in Fig. 1 and 2, the plunger 29 is inclined slightly with respect to the horizontal so that the impact of the actuating solenoid 1 merely tends to vibrate the plunger laterally against the sides of its cylindrical guide instead of causing longitudinal movement of the plunger and trip ping of the latch. Accordingly, the tripping means is substantially shock-proof notwithstanding the sensitivity of the trip. A light spring 28' may be employed to return the plunger 29 to its initial position, and where the slope is suficient gravity may be relied upon. A slight inclination of the trip coil likewise prevents accumulation of water in the coil.

The operation of the mechanism is as follows: In the open circuit position of the switch the rod 2 is in its upper position so that the floating lever 6 is rotated approximately 90 counterclockwise from the position shown in'Fig. 1, with the roller 16 resting on the end of the plunger stem 12. The remainder of the mechanism is substantially in the position shown, the link 3 being restrained by latch 23 so that pivot 7, which is slightly ofiset with respect to the pivot 4 of the link 3, is held stationary. Accordingly, upon energization of the solenoid 1 the plunger 11 is projected upwardly against the armature 13 so that the floating member 6 is rotated clockwise and the rod 2 lowered to the closed circuit position shown. As the lever 6 is rotated to the closed position, the pin 21 rides along the camming edge 1'7 of the prop 1'1 against the bias of the prop spring 19 so that when the pin reaches the closed position the edge 20 of the prop slides underneath the pin'2l thereby holding the lever 6 against reverse movement. The solenoid may be deenergized until the next operation.

'When the mechanism is to be tripp d to the open circuit position the solenoid 28 is suitably energized, as by a current transformer responsive to excess current, so as to project the trip coil armature 29 into the coil. As best shown in Fig. 2, the extension 29' of the trip coil plunger rotates the latch 23 counter-clockwise so as to release roller 2'1. The'mechanism in Fig. 2 is shown immediately after tripping and before the complete collapse of the operating linkage. The reacting force of the switch tending to cause opening movement of the rod 2 has a component acting upwardly on the floating pivot 7 tending to rotate the link 3 in a counterclockwise direction. Accordingly, when the latch 23 is actuated and the roller 2'7 is released the link 3 first rotates a short distance in a counterclockwise direction, thereby causing corresponding movement of the pivot 7. This movement in turn causes shifting of the floating lever 6 towards the right with the result that the pin 21 slides oif the edge 20 of the prop 17. The float ing lever 6 is now free to rotate counter-clockwise under the opening force so that the roller 16 again engages the plunger extension 12. During the above described rotation of the floating lever 6 the link 3 returns to its initial position under bias of its spring 3, the link 3 engaging a stop pin 3" after resetting and before there is any load on member 2 pressing the roller 27 against latch 23, and the latch 23 is biased by its spring 25 so as again to block movement of the roller 27. Return of the latch to its blocking position also aids the return of the trip coil plunger 29, assuming, of course, that the trip coil has been deenergized. The mechanism is now in the reset position and is in readiness for another closing operation upon energization of the solenoid 1.

It is believed that the trip-free operation of the mechanism is apparent. Assuming that the latch 23 is tripped during the upward stroke of the solenoid plunger 11, the release of link 3 causes the roller 16 to move off the end of the plunger extension 12 so that the rod 2 moves back to the open position in the manner above described independently of the solenoid.

The manner in which a sensitive trip is obtained, notwithstanding a minimum number of moving parts, is diagrammatically shown in Fig. 3. The reacting force R tends to cause counterclockwise rotation of the link 3, the moment arm having a length d which is the distance between the center line through pivot 4, which is parallel to the direction of the force R, and the parallel center line of the pivot '7. Since this off-center distance may be comparatively small and the link 3 may be extended a suitable distance as shown so as to reduce the tripping force required, it will be apparent that a comparatively small tripping force T is required to overcome the friction between the roller 2'7 and the latch 23. With this arrangement a minimum number of moving parts is involved since the actual trip is in efiect at the floating pivot 7 itself. Since a trip-free mechanism necessarily involves a collapsible structure or its equivalent between the actuating means and the means to be actuated, the trip-free mechanism embodying my invention is in one of its simplest forms while at the same time maintaining a sensitivity of the trip not found in far more complicated mechanisms.

In Fig. 4 there is shown a similar mechanism wherein the tripping means 5 is slightly modifled. In this-arrangement the link 3, instead of being directly restrained 'by the latch, is provided with an 31-32. Link 31 of the toggle is connected as at intermediate tripping toggleand opening of the mechanism.

In Fig. the trip means 5 comprises electromagnetic means arranged so that the lever 3 is directly released upon currents of overload or other abnormal circuit conditions. As shown, the lever 3 is provided at its free end with armature 37 coacting with an electromagnet 38 having a flux weakening coil 39. This type of releasing magnet is well known, predetermined energlzation oi coil 39 weakening the fiux in the gap between the poles of the magnets so that the armature 37 is instantly released. The mechanism is accordingly tree to open in the aforesaid manner, the only difi'erence in structure being the arrangement of the prop 17 which is suspended above the pin 21, the operation otherwise being the same.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. Operating mechanism comprising actuating means including a solenoid plunger, a floating lever pivotally connected at one end to means to be actuated, said lever arranged to be engaged at its opposite end by said plunger, a pivoted member on which said floating lever is pivotally mounted, tripping means restraining the tree end of said pivoted member so that said actuating means is eiiective upon engagement therewith to rotate said floating lever about a fixed pivot on said pivoted member, and means holding said floating lever in its final position arranged so that said plunger is tree to return to its initial position.

2. Operating mechanism comprising actuating means and a member to be actuated, trip-tree structure operatively interconnecting said actuating means and member comprising a link having a fixed pivot at one end, a floating lever pivotally mounted intermediate its ends on said link, and tripping means for restraining the free end of said link', said actuated member being pivotally connected to one end of said floating lever, said actuating means including a solenoid plunger arranged to engage the opposite end of said lever toactuate said member when said link is restrained, and means holding said lever in its final position arranged so that said plunger is free to return to its initial position.

3. Operating mechanism comprising an actuating solenoid and a rod member to be actuated, trip-free structure inter-connecting said solenoid and rod member comprising a floating lever operatively related at one end to said solenoid and at its other end to said rod member, a link pivoted at one end and provided with a latchengaging roller at its other end, said floating lever pivotally mounted intermediate its ends on said link, a latch for restraining the latchengaging portion of said link so that said solenoid is eiiective to rotate said floating lever and actuate said rod member, and a prop pivotally biased so as to hold said floating lever in its actuated position, release of said latch causing shifting of said floating lever from said prop and rotation of said lever to its initial position.

4. Operating mechanism of the trip-free type comprising a link having a fixed pivot at one end thereof, tripping means for restraining the opposite end of said link, a member interconnecting actuating means and means to be actuated pivotally mounted on said link intermediate its end, and means for holding said member in its finally actuated position arranged so that said actuating means is free to return to its initial unactuated position, the pivotal mounting of said member being located so that the reacting force of said means to be actuated acts on a very small lever arm as compared with the lever arm at the means to be actuated tending to cause rotation of said link.

5. Operating mechanism of the trip-tree type subject to an appreciable closing impact comprising in combination an actuating solenoid having a vertically movable plunger, collapsible thrust transmitting structure interconnecting said plunger and means to be actuated, tripping means controlling said structure including a trip coil having a plunger, said trip coll plunger being guided for substantially horizontal movement so that it is not subject to premature tripping movement by the operating impact or said first-named plunger.

- CARL THUMHL 

